At offset 36 (0x24) located number of data blocks minus one, 4 bytes, little-endian order (lowest byte first).
Block size is always 1024 bytes. File size is calculated as total number of blocks multiplied by block size.

When inspecting file's binary data using any Hex Viewer, like Active@ Disk Editor we can see the signature MAUI (hex: 4D 41 55 49) at offset 96 (0x60). Total number of data blocks (minus one) is 3,422 (hex: 5E 0D 00 00 at offset 52 (0x34)).

QBW file size is 3,505,152 bytes: 1,024 * (3,422+1).

Thus reading of all 3,505,152 consecutive bytes starting from the sector where MAUI signature has been detected provide us with all QBW file data.

Active@ File Recovery Custom Scripting Example

This example does some validation calculations for QBW header's parameters beyond simple file size extraction. Syntax of the signature definition language you can read here.